Improving positioning accuracy of aircraft using SPP method in GLONASS system

The paper presents the results of a study showing the accuracy of the determination of aircraft position coordinates based on the SPP (Single Point Positioning) solution in the GLONASS (Globalnaja Navigatsionnaya Sputnikovaya Sistema) system. For this purpose, the paper develops and implements an algorithm for the correction of position errors as parameters describing positioning accuracy. The proposed algorithm uses position error values determined for a single GNSS (Global Navigation Satellite Systems) receiver, which are joined in a linear combination to determine the positioning accuracy of the aircraft. The algorithm uses linear coefficients as an inverse function of the number of GLONASS satellites being tracked by the GNSS receiver. The developed algorithm was tested for GLONASS satellite data recorded by Topcon HiPer Pro and Javad Alpha geodetic receivers, during a flight test carried out with a Cessna 172 aircraft around the military airport in Dęblin. Navigation calculations were carried out using RTKLIB v.2.4.3 and Scilab v.6.0.0 software. On the basis of the tests carried out, it was found that for single Topcon HiPer Pro and Javad Alpha receivers, position errors were up to ±11.4 m. However, by using the position error correction algorithm for both receivers, GLONASS positioning accuracy is up to ±3.6 m. The developed algorithm reduces position errors by 60-80% for all BLh (B- Latitude, L- Longitude, h- ellipsoidal height) coordinates. The paper shows the possibility of testing and implementing the proposed mathematical algorithm for the SPP solution in a GPS (Global Positioning System) navigation system. In this case the position errors from the GPS SPP solution range from -0.9 m to +0.9 m for all BLh coordinates. The obtained results showed that application the GLONASS and GPS system in air transport is important. The algorithm used in this work can also be applied to other global GNSS navigation systems (e.g. Galileo (European Navigation Satellite system) or BeiDou (Chinese Navigation Satellite System)) in air transport and navigation.